HTLV-I is a retrovirus etiologically associated with adult T-cell leukemia, tropical spastic paraparesis and possibly multiple sclerosis in humans. It has been documented that certain HTLV-I-infected patients develop Sjogren's syndrome, a disease of presumed autoimmune etiology resulting in severe dysfunction of the lacrimal and salivary glands. Three founder lines of transgenic mice carrying the HTLV-I taxl gene have been extensively studied and have been shown to develop neurofibromas as well as pathology very similar to that seen in patients with Sjogren's syndrome. Further characterization of these transgenic mice offers the opportunity to study the mechanisms resulting in this disease process and may provide new insights into understanding autoimmunity.